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Problem with eigenfrequency in MEMS device

Posted 18 juil. 2012, 16:15 UTC−4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Results & Visualization Version 4.3 3 Replies

Neil Tidwell
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I am trying to model a PZT device in order to find the resonance frequency. For some reason I get different eigenfrequencies for the same structure when I add 0-thickness electrodes and also when I put a constant electric potential one of the electrodes.

I thought eigenfrequency only relies on the structural properties of the device, so why does it change when when I add 0-thickness electrodes or add a charge to the device?

Thanks
3 Replies Last Post 21 sept. 2012, 11:17 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 19 juil. 2012, 01:28 UTC−4
Hi

the eigenfrequency is depending also on the electric connections you do on a PZT because that changes the stiffness of the PZT. So you should have two frequencies, one in open circuit mode and one slightly different in short circuit mode, their relation gives the K coupling factor. Check a book on PZT systems, I can recommend the books of Prof. Preumont

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Good luck
Ivar
Hi the eigenfrequency is depending also on the electric connections you do on a PZT because that changes the stiffness of the PZT. So you should have two frequencies, one in open circuit mode and one slightly different in short circuit mode, their relation gives the K coupling factor. Check a book on PZT systems, I can recommend the books of Prof. Preumont -- Good luck Ivar
Neil Tidwell
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Posted: 1 decade ago 19 juil. 2012, 11:05 UTC−4
Thanks Ivar, I will look into it.
Thanks Ivar, I will look into it.
Zhang Gazi
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Posted: 1 decade ago 21 sept. 2012, 11:17 UTC−4
Hi Ivar,

I am now doing SAW eigenfrequency analysis and meet a problem of temperature effect on LiNbO3. There is a similar tutorial in comsol named saw_gas_sensor. Now I want to add the temperature effect, say increase the temperature to 40 degree and then analyse the eigenfrequency change. I have been struck here for a long time. Hope you could help me out. Thanks.

Regards,
--
zhanggazi
Hi Ivar, I am now doing SAW eigenfrequency analysis and meet a problem of temperature effect on LiNbO3. There is a similar tutorial in comsol named saw_gas_sensor. Now I want to add the temperature effect, say increase the temperature to 40 degree and then analyse the eigenfrequency change. I have been struck here for a long time. Hope you could help me out. Thanks. Regards, -- zhanggazi

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